TOPEX · Extreme confinement of topologically protected slow light

Extreme confinement of topologically protected slow light

The importance of quantum technologies in our future society is nowadays becoming clear and goes far beyond the highly praised quantum computers. One platform for quantum technologies is integrated photonics, where the interaction between light and matter can be tailored using advanced top-down nanofabrication like that employed for commercial electronics. Integrated photonic cavities and waveguides, where the electromagnetic field intensity is enhanced through either spatial or spectral confinement -or both- are particularly attractive. However, the former trade light-matter interaction strength for optical bandwidth, and the latter trade that strength for propagation losses. Therefore, strong light-matter interaction over long distances and over a large bandwidth is complicated to achieve. TOPEX primarily aimed at developing a novel platform for quantum photonics based on topological bowtie photonic-crystal waveguides, for which such propagation losses may be suppressed due to their topological nature and for which the field intensity is only limited by the smaller feature size -at the few nanometer scale- that can be reliably manufactured. More specifically, the main objective of TOPEX was to experimentally explore the existence of topologically protected light transport in the slow-light regime of a waveguide made from a conventional semiconductor material, i.e., silicon, where light-matter interaction becomes notable and technologically meaningful. In addition to that, the project aimed at studying the role of bowtie-shaped features at such topological interfaces to exponentially enhance the field intensities locally and thus boost the interaction with point-like emitters.

Data: CORDIS, © European Union